You can gang together a bunch of pots, but they won't track well, and not for long. A sound card usually has digital volume control built into the software that comes with it- is there a problem with that?

About the only way you're going to get a bunch of pots that track reliably over a long period of use is to go digital.

In my case, I'm actually using a PC to drive my power amp, but with 200w online (I got one of those big Brigar electronics power transformers), I don't want to blast people out of the room if they hit 'up' on the volume too fast. I've also seen some PC programs spontaneously up the volume, based on some remembered setting.

In my case, I got some ALPS detented audio pots, so I'll have a 'Max Volume' on the power amp. I'll probably build a simple 'passive preamp' or build it into the amp, I haven't decided yet.

The nice thing with 3 2 channel controls is that 'front / center / rear' balance can be controlled as well as the max volume, with a minimum of parts.